1. Technical Field
The present invention relates to an image processing method, and relates more particularly, but not exclusively, to an image processing method for an optical touch system.
2. Related Art
Touch screen devices are a type of electronic device that allows users to perform input operations directly on a screen. When a stylus, a finger tip or a similar object touches the screen, the touch screen device detects and calculates the position of the touch point, outputting coordinates to a computing system to allow the computing system to perform subsequent computing operations.
Optical touch screens are a common type of developed touch screen devices. An optical touch screen usually comprises a light source and a camera arranged in a manner such that when an object touches the optical touch screen, an object shadow will be cast on the camera. When no object touches the optical touch screen, the camera may generate an image, which is relied upon to extract a background light intensity waveform pattern 11 as shown in FIG. 1; when an object touches the optical touch screen, the camera will generate an image, which is relied upon to extract a light intensity waveform pattern 12 including a shadow signal 121.
When an object touches the optical touch screen, the manner of light reflection may be changed such that a false signal is generated. For example, an object may deform the screen, causing light to be reflected into the camera and generating a reflected light signal 13, or changing the manner of light reflection and causing a false shadow signal 14. The false shadow signal 14 may be misinterpreted as a signal that is generated by an object. As a result, incorrect object coordinates may be computed, or the number of objects is incorrectly determined and real coordinates of the object are incorrectly calculated.
Therefore, a new method that can avoid the issue of false signals being generated in conventional optical touch screens is needed.